Dempsey, 29, has been at Craven Cottage since 2007 but, with his contract due to expire next year, has signalled his intention to move on this summer and wants to test himself in the Champions League.

The USA international was left out of the club's pre-season training camp in Switzerland amid speculation about his future and will not feature in Fulham's Premier League opener at home to Norwich City on Saturday. Manager Martin Jol confirmed that Dempsey wants to leave, but said the forward will only be sold if the club receives a suitable bid.

"Clint was not involved over the last four weeks, so he is not going to be in the squad," Jol said. "He is not committed to the club. He wants to leave. I would like to keep him, but I think it's impossible. It's a sad and an almost embarrassing situation."

However, an ESPN source has confirmed that Dempsey's desire to leave means he is refusing to play for the club again.

"The player is refusing to play for the club," the source revealed. "He has refused to play in the opening game tomorrow, and he is refusing to play because he wants to go.

"It is very embarrassing for the club but the club is working hard to find a solution, but it is a difficult one. Clint has been linked to Liverpool all summer but Fulham have not received an offer from Liverpool for him or indeed an offer for him from any club.

"What action, if any, the club is taking will remain private, but the priority is to find a solution, rather than confirm or deny the club plan to fine the player."

Liverpool have been the club most strongly linked with Dempsey, with manager Brendan Rodgers having confirmed an inquiry was made.

At one stage, the website for the Massachusetts-based news channel New England Sports Network (NESN), owned by Fenway Sports Group, published a story suggesting the deal was done, but it was removed soon afterwards.

"That was very disappointing," Jol said. "There was never an offer. Clint himself told everyone he was going to Liverpool before he came back, so we really thought there was quite a firm interest in him.

"Even [Rodgers] told everyone he was interested in Clint Dempsey, but our people never had an offer on the table, so it's almost embarrassing. If you have shown interest in a player, especially in England, you have to follow it up with an offer. They didn't."

He added: "Maybe Liverpool will come back. I can assure you that our chairman is strong enough. At first we didn't want to get rid of him, later on we had to change our position - but our view is that we won't let Clint Dempsey go on the cheap, that's for sure."

Jol was also quick to express his disappointment at the recent conduct of Moussa Dembele's agent, denying that there had ever been interest from Real Madrid. Jan de Visser, Dembele's representative, had made comments to Dutch newspaper De Telegraaf indicating that a bid had been made by the Spanish side.

The Fulham boss said: "I spoke to his agent and I said to him it's not the cleverest thing to do, to speak about players. There was no offer on the table (from Madrid) and hopefully the situation will stay as it is. Hopefully Dembele will stay here.

"There was one low bid from one Premier League club, very low. Moussa is quite happy here. He wants to play here and if something happens, we will have to wait.''